While smartphones have great utility as long as they are within range of appropriate networking infrastructure, some uses can require that the smartphone location be more precisely identified. For example, numerous emerging smartphone applications require position information in order to provide location-based or context-aware services to the smartphone user. In these applications, GPS is often preferred over its alternatives such as cell tower-based positioning systems because it is known to be more accurate. Indeed, cell tower-based localization has errors as high as 500 meters. For this reason, the use of GPS for location-based applications is likely to continue, although it may be augmented with other positioning methods.
Unfortunately, GPS technology requires substantial power, and keeping GPS activated on a smartphone continuously can drain the battery in less than 12 hours in many cases, even in the absence of other activity. This high energy consumption presents a hurdle to all-day smartphone usage.